20th Century

In the summer of 1939, explorer Ken Masters and Tim Roberts went looking for Professor John Roberts who had gone missing in the upper Amazon while trying to locate a diamonds that supposedly had the power to control minds. Masters and younger Roberts landed their plane into the Amazon rainforest after some engine problems. They were followed by rival plantation owner John Crafton who also sought to find the hypnotic diamond. They were all captured by a local English-speaking tribe to be sacrificed, discovering that the professor was their prisoner as well. Groups of Masters and Crafton were put on the different prison huts but both had escape hatches so they all fled. Ken Masters, John and Tim Roberts got away and professor was even able to pocket one gem from the diamond cave, but Crafton and his goons were killed by the natives.[1][2]

Many alien species have used the Amazon as a base of operations for there invasion these include:

Taboo was using the jungle as his hiding place, until he was discovered by Lewis Conrad. Taboo told Lewis that he was stuck there and needed human knowledge to rebuild his ship and rturn home. This turned out to be a lie and was attempting to plan an invasion but was destroyed when he left.[3]

Bombu who proclaimed himself the leader of a tribe of natives, and used his powers to attempt to rule the world since he thought the entire world had the same technology level as the tribe. He was defeated by his own powers when he was struck by lightning and fled the planet.[4]

Modern Age

Captain America parachuted into the jungle looking for Baron Zemo, defeated his guards and shattered his primitive palace with the vibra-gun. While Zemo attempted to escape by plane, he magnetically attached his shield to follow him back to the United States of America.[5]
Zemo returned to his hideout with the Enchantress and the Executioner to plot their revenge against the Avengers. They recruited inventor Simon Williams and bombarded him with the most powerful ionic rays to make him the Wonder Man. After having earned the Avengers' trust, Wonder Man got back to the jungle with the Wasp, who was taken captive: the Avengers came here to save her, only to be betrayed by Wonder Man. The Masters of Evil came very close to defeating the Avengers, when Wonder Man decided to betray them, as the Avengers did all they could to save him, even though they didn't know him. Wonder Man saved the Avengers, then subsequently died from the poison inflicted by Baron Zemo, who managed to escape through a secret passage with his allies.[6]
Back in a strange, heavily fortified castle hidden deep within the Amazon jungles, the Masters of Evil were visited by Immortus, wanting to ally himself with them to destroy the Avengers. Once he took Captain America away, the Masters of Evil departed to battle the supergroup in New York. Having failed again, the Enchantress took them back in the past, before that fateful moment when Immortus appeared, and they returned to the strange castle.[7]
A short time later, Zemo sent his Army of Assassins to the United States to pose as a group of athletes for an exhibition fight against Captain America and defeat him. As soon as he turned his TV on, he saw Cap telling that Zemo had failed and that he was a coward for not battling him face-to-face. Angered by Cap's taunts, Zemo blasted the screen.[8]
Some time later, Rick Jones was kidnapped by Franz Gruber and brought here to lure Captain America into an ambush set up by Zemo. The Avenger eventually managed to rescue the kid, and Baron Zemo accidentally triggered an avalanche which landed on and killed him.[9]
After the battle, Captain America dug a grave for Zemo and freed the natives who were enslaved by the arch-villain. As Zemo's jet was blown up by a grenade tossed by his mercenaries, Cap and Rick Jones approached the border of a coastal plantation, saving a white man from a leopard; the grateful plantation worker led them to the seaport of Caruca, where they could find transportation to the United States.[10]
After some time, all Zemo's soldiers-of-fortune had left the jungle, except for Erik Josten, wanted by the Interpol, so he returned to the machinery used to create Wonder Man. There he found the Enchantress, who told him she would use the machine to make him strong too. He agreed and became Power Man.[11]